The Last Day Of 2023 Will Be Even More Rare Than A Palindrome Date

Check your calendar, the last day of this year will be 12/31/23.

Think about that a bit longer: 123123. 123-123.

It will be a very long time before that ever happens again.

We have other strange dates that appear on our calendar now and again.

Palindrome Dates are the same forward and backward.

For example, Sunday, February 2, 2020.

Look at 02022020 in a mirror and see what you get.

Here is a short list of past and upcoming palindrome dates.

January 20, 2021 (1202021)
December 2, 2021 (12022021)
February 20, 2022 (2202022)
March 20, 2023 (3202023)
April 20, 2024 (4202024)
May 20, 2025 (5202025)

Then there are Binary Dates.

Hang on, this gets complicated.

Date binary representation. This value is an integer value that represents the number of days since December 31, 1899. Dates before December 31, 1899, are negative numbers, while dates after December 31, 1899, are positive numbers.

Then there is the odd Leap Year.

It takes approximately 365.25 days for Earth to orbit the Sun — a solar year.

We usually round the days in a calendar year to 365.

That means we have to make up for that .25 now and then.

So we add one day to our calendar approximately every four years.

That is a leap year.

Approximately every four years, February has 29 days instead of 28.

That means there are 366 days in that year.

Okay, hold on, this next one is going to hurt your brain.

January 0 or 0 January is an alternative name for December 31.

January 0 is the day before January 1 in an annual ephemeris.

It keeps the date in the year for which the ephemeris was published, thus avoiding any reference to the previous year, even though it is the same day as December 31 of the previous year. January 0 also occurs in the epoch for the ephemeris second, "1900 January 0 at 12 hours ephemeris time".

1900 January 0 (at Greenwich Mean Noon) was also the epoch used by Newcomb's Tables of the Sun, which became the epoch for the Dublin Julian Day.

OKAY - let's stop.

My head hurts.